1. Field of the Invention
The present invention relates to an apparatus and a method for generating images.
2. Description of the Related Art
With the prevalence of digital still cameras and digital video cameras, there are increased occasions where still images or moving images having been shot are stored in a computer for later viewing, processing, or displaying on the screen of a game device or a television system. It is also popularly done that the shot moving images are uploaded to a posting site on the Internet so as to share them with the other users.
Among the digital cameras are those capable of shooting panoramic images, which allow the image taking of panoramic images of wide view angle with perfect ease. Also in wide use are software tools that can generate a panoramic image by stitching together a plurality of images shot by a digital camera from different shooting directions.
There is a site named “360cities” (http://www.360cities.net) that accepts the posting of panoramic images shot by users and show them on the Internet, so that the users around the world can view the panoramic images posted.
A panoramic image is a spherical, or omnidirectional, image. When shot outdoors, therefore, it may have the sun, street lamps, or such other things captured in it. As a result, the panoramic image may have an extremely wide dynamic range with great differences between bright portions and dark portions. Thus, if a panoramic image is shot with exposure adjusted to a specific object, then the resulting image may sometimes have “white-out” in the bright portions and “black-out” in the dark portions. As used herein, “white-out” is complete whitening of portions exposed to strong light, whereas “black-out” is complete blackening of dark portions least exposed to light.
In a normal photo shoot, therefore, an object or objects are captured with correct exposure, or adjustments are made to prevent strong light from entering a field of view, in order to avoid white-out or black-out. However, in the shooting of a panoramic image that covers all directions, it may be out of the question to determine correct exposure matching a specific object or objects. To make up for this shortcoming, a panoramic image is, for instance, synthesized by the use of a high dynamic range synthesis technique. In this technique, a plurality of low dynamic range photos are taken with exposure changed accordingly, and then those photos are put together into an image having a high dynamic range without white-out or black-out. Yet, this high dynamic range synthesis requires use of a high-priced camera or cameras and long shooting and processing time.